1. Field of the Invention
This invention relates to a polyvalent vaccine or medication for the treatment and prevention of mastitis in bovine animals, and a method of producing that vaccine. Specifically, this invention is directed to a process for preparing a therapeutic and prophylactic vaccine of broad applicability, and the vaccine produced thereby.
2. Description of the Prior Art
Infection of the mammary gland in bovine animals, particularly dairy cattle, which is commonly referred to as mastitis, represents a major health problem to the dairy industry. Mastitis causes a loss of milk production by infected cows, and it is estimated that the average dairy farmer loses approximately $400/cow per year due to mastitis. This represents an overall financial loss of about $26,000 per year for a dairy herd consisting of 200 milking cows. On a national. scale, this loss is staggering.
Conventionally, methods and products for the prevention and treatment of mastitis include the use of sanitary milking techniques and chemical antibiotics, which are either perfused into the infected udder through the tit canal or injected into the muscle of the animal. However, the antibiotics which are used to treat mastitis cannot be employed to prevent the occurrence of mastitis because antibiotic derivatives which appear in the milk following treatment are not safe for human consumption. As a result, antibiotic contaminated milk must be discarded, and this represents a further financial loss to farmers. Although, in some situations, antibiotic contaminated milk may be fed to calves, this practice poses the severe hazard of harming the calves. Accordingly, conventional methods remain unsatisfactory to prevent the occurrence of mastitis, and represent a large financial loss when used to treat mastitis.
Further, chronic infection of the cow udder causes the milk-producing tissues to feel hard to the touch when the udder is palpated. This condition in dairy cattle is commonly referred to as "hard udder". Under conventional practices, once the udder hardens, milk production is reduced and remains compromised even after the infection ceases. There is no known method or product in the prior art that will reverse the hard udder condition once it occurs, and this condition generally presists for the life of the cow.
Recently, attempts have been made to develop vaccines for immunization against mastitis. However, these have for the most part been unsuccessful, particularly due to the wide spectrum of different pathogens that can cause mastitis. A number of polyvalent vaccines, which include different combinations of bacterial strains and other pathogens known to cause mastitis have been developed and tested. However, none of these have proved to be highly effective in preventing the disease over an extended period of time. Further, they have not been successful in treating mastitis and reversing hard udder syndrome. In spite of the great financial impact mastitis has on the dairy industry, there has been little or no progress in the prevention and/or treatment of mastitis.
Accordingly, an industry-wide need persists for a vaccine for the treatment and prevention of mastitis in bovine animals over an extended period of time, and a method of reversing hard udder syndrome.